Aspects of the present invention pertain to the treatment of parasites on humans and/or animals using externally-applied agents. In certain of its embodiments, the present invention relates to methods and compositions that can be used in the prevention or control of mite infestations of the skin.
Parasitic infestations of the skin and/or hair are responsible for a number of conditions or disorders in both humans and animals. As an example, scabies is a contagious skin infection occurring in humans and animals. In humans, the disease is caused by the parasitic mite Sarcoptes scabiei which burrows under the host's skin causing allergic itching which is usually worse at night. The cutaneous diagnostic signs include multiple papules, minute vesicles and occasional linear tracts. The disease is most frequently transmitted by skin-to-skin contact, and is associated with close personal contact. No age or socioeconomic class escapes the disease.
Complications of scabies include bacterial superinfection, sepsis, glomerulonephritis and progression to Norwegian or crusted scabies—a more severe, life-threatening form of the disease. In animals, the disease is commonly known as sarcoptic mange which is caused by other mites in the order Sarcoptiformes.
Current treatments of scabies in humans include the topical application of permethrin for most cases and the oral administration of ivermectin in more severe cases including cases where the patient suffers from an immune system disease, e.g., HIV/AIDS. Other treatments include the use of crotamiton and lindane.
The spinosyns are a family of macrolides produced by the fermentation of Saccharopolyspora spinosa. The spinosyns are commonly used as insecticides in agricultural settings and are used for the treatment of lice in humans. More recently, the spinosyns have been used to treat lice and their eggs.
Each spinosyn compound has a 12-membered macrocylic ring that is part of a tetracyclic ring system to which two different sugars are attached, the amino-sugar forosamine and the neutral sugar 2N,3N,4N-tri-O-methylrhamnose. Spinosyn A was the first spinosyn isolated from the fermentation broth of S. spinosa. However, subsequent studies have identified a number related derivatives that have been labeled A to J.
Needs exist for improved and/or alternative methods and compositions that are useful for controlling mites and other parasites in humans and animals. Aspects of the present invention are addressed to these needs.